I have also seen
mention of a device to help train the eye to recognize cards more accurately. It was mentioned on Arnold Snyder's web site a year or two back I think, where someone was having such a gadget duplicated so it could be sold to those interested. With practice, the human eye is incredibly accurate. I used to know a machinist that could look at a bolt, or washer, or such, and tell you the thickness with accuracy of better than .005". And I'd test him with a micromoter to verify. I often tried to get him to take up counting cards because boy could he do deck estimation accurately if he wanted.
There's more to it than just flashing the whole card, you really want to just get a glimpse of the corner or whatever the dealer is revealing. Someone ought to write such software if it isn't already available, although on a PC the angle and such would not really prepare you as well for the real thing as something more specifically designed.
